For example, the development of a probe memory has been advanced which records data onto a recording medium or which reproduces the data recorded on the recording medium by displacing a probe array including a plurality of probes along a recording surface of the recording medium. In such a probe memory, the location of the probe array with respect to the recording medium (in other words, a position relation between the probe array and the recording medium) is determined, for example, by displacing a stage provided with the probe array. In other words, the location of the probe array with respect to the recording medium is determined by the operations of a MEMS (Micro Electro Mechanical System) actuator which is provided with the stage and which can displace the stage.
As a specific structure for displacing the stage provided with the probe array, for example, a MEMS actuator disclosed in a non-patent document 1 is listed as one example. In such a MEMS actuator, the stage is displaced by applying a force to the stage such that the stage oscillates at a relatively low frequency (more specifically, at a frequency lower than the minimum resonance frequency of a spring-mass system including the stage). As described above, the reason why a force is applied to the stage to oscillate the stage at a frequency lower than the minimum resonance frequency is because it is considered that if the force is applied to the stage to oscillate the stage at a frequency near a resonance frequency, the gain of the oscillation (i.e. oscillation range) becomes too large, or it becomes harder to control a position at a frequency higher than the resonance frequency, resulting in unstable operations of the stage (i.e. operations of the MEMS actuator). By this, it is possible to stabilize the operations of the MEMS actuator.    Non-Patent document 1: Tatehiko Hasebe, Seiko Yamanaka, Takeshi Harada, Yasushi Mutou, “Development of wide lateral stroke electro-magnetic actuator driven by low voltage”, IEEJ Sensors and Micromachines Society Sogo-Kenkyukai/Micromachines and Sensor systems Kenkyu-kai, No. MSS-06-12